In 2006, Bao et al proposed an identlty-based threshold proxy signature scheme with known signers. In this paper, we show that Bao et al's scheme is vulnerable to the forgery attack. An adversary can forge a valid th...In 2006, Bao et al proposed an identlty-based threshold proxy signature scheme with known signers. In this paper, we show that Bao et al's scheme is vulnerable to the forgery attack. An adversary can forge a valid threshold proxy signature for any message with knowing a previously valid threshold proxy signature. In addition, their scheme also suffers from the weakness that the proxy signers might change the threshold value. That is, the proxy signers can arbitrarily modify the threshold strategy without being detected by the original signer or verifiers, which might violate the original signer's intent. Furthermore, we propose an improved scheme that remedies the weaknesses of Bao et al's scheme. The improved scheme satisfies all secure requirements for threshold proxy signature.展开更多
Based on the GDH signature (short signature scheme) a probabilistic signature scheme is proposed in this paper with security proof.Then a new threshold proxy signature from bilinear pairings is proposed as well by us ...Based on the GDH signature (short signature scheme) a probabilistic signature scheme is proposed in this paper with security proof.Then a new threshold proxy signature from bilinear pairings is proposed as well by us ing the new probabilistic signature scheme and the properties of the Gap Diffie-Hellman (GDH)group (where the Computational Diffie-Hellman problem is hard but the Decisional Diffie-Hellman problem is easy to solve).Our constructions are based on the recently proposed GDH signature scheme of Bonel et al.s article.Bilinear pairings could be built from Weil pairing or Tate pairing.So most our constructions would be simpler,but still with high security.The proposed threshold proxy signature is the first one which is built from bilinear pairings.At the end of this paper security and performance of the threshold proxy signature scheme is also analyzed.展开更多
In 2005, Bao, et al. [Appl. Math. and Comput., vol.169, No.2, 2005] showed that Tzeng, et al.’s nonrepudiable threshold multi-proxy multi-signature scheme with shared verification was insecure, and proposed an improv...In 2005, Bao, et al. [Appl. Math. and Comput., vol.169, No.2, 2005] showed that Tzeng, et al.’s nonrepudiable threshold multi-proxy multi-signature scheme with shared verification was insecure, and proposed an improved scheme with no Share Distribution Center (SDC). This paper shows that Bao, et al.’s scheme suffers from the proxy relationship inversion attack and forgery attack, and pro- poses an improvement of Bao, et al.’s scheme.展开更多
Kang, et al. [Journal of Electronics(China), 23(2006)4] proposed a threshold multi-proxy multi-signature scheme, and claimed the scheme satisfies the security requirements of threshold multi-proxy multi-signature. How...Kang, et al. [Journal of Electronics(China), 23(2006)4] proposed a threshold multi-proxy multi-signature scheme, and claimed the scheme satisfies the security requirements of threshold multi-proxy multi-signature. However, in this paper, two forgery attacks are proposed to show that their schemes have serious security flaws. To overcome theses flaws, an improvement on Kang, et al.’s scheme is proposed.展开更多
In the YW threshold proxy quantum signature scheme proposed by Yang and Wen,it is found that the basic signature key is the same as the basic verification key,which means that the bitwise exclusive OR(XOR) of the t pr...In the YW threshold proxy quantum signature scheme proposed by Yang and Wen,it is found that the basic signature key is the same as the basic verification key,which means that the bitwise exclusive OR(XOR) of the t proxy signature keys is exactly the XOR of the t proxy verification keys.Therefore,the proxy signers can deny their signature and the specific verifiers can forge a legal signature.Furthermore,an attacker can obtain a legal threshold proxy signature for an arbitrary new message.These findings show that there are hidden security loopholes that should be carefully constructed in designing more efficent YW-scheme.展开更多
The universal composability framework is a new approach for designing and analyzing the security of cryptographic protocols.In this framework,the security of protocols is maintained under a general protocol compositio...The universal composability framework is a new approach for designing and analyzing the security of cryptographic protocols.In this framework,the security of protocols is maintained under a general protocol composition operation.In the paper,we propose the universal composability framework for the analysis of proxy threshold signature and present a universally composable secure proxy threshold signature scheme which is the first one in this area.The proposed scheme is suitable for the mobile agents,which should migrate across different environment through network.Furthermore,we give the concrete analysis of the reduction to prove the security of the proposed scheme.展开更多
基金Supported by the National Natural Science Foun-dation of China (60473029)
文摘In 2006, Bao et al proposed an identlty-based threshold proxy signature scheme with known signers. In this paper, we show that Bao et al's scheme is vulnerable to the forgery attack. An adversary can forge a valid threshold proxy signature for any message with knowing a previously valid threshold proxy signature. In addition, their scheme also suffers from the weakness that the proxy signers might change the threshold value. That is, the proxy signers can arbitrarily modify the threshold strategy without being detected by the original signer or verifiers, which might violate the original signer's intent. Furthermore, we propose an improved scheme that remedies the weaknesses of Bao et al's scheme. The improved scheme satisfies all secure requirements for threshold proxy signature.
文摘Based on the GDH signature (short signature scheme) a probabilistic signature scheme is proposed in this paper with security proof.Then a new threshold proxy signature from bilinear pairings is proposed as well by us ing the new probabilistic signature scheme and the properties of the Gap Diffie-Hellman (GDH)group (where the Computational Diffie-Hellman problem is hard but the Decisional Diffie-Hellman problem is easy to solve).Our constructions are based on the recently proposed GDH signature scheme of Bonel et al.s article.Bilinear pairings could be built from Weil pairing or Tate pairing.So most our constructions would be simpler,but still with high security.The proposed threshold proxy signature is the first one which is built from bilinear pairings.At the end of this paper security and performance of the threshold proxy signature scheme is also analyzed.
基金Supported by the National Natural Science Foundation of China (No.10671051)the Natural Science Foundation of Zhejiang Province (No.Y105067).
文摘In 2005, Bao, et al. [Appl. Math. and Comput., vol.169, No.2, 2005] showed that Tzeng, et al.’s nonrepudiable threshold multi-proxy multi-signature scheme with shared verification was insecure, and proposed an improved scheme with no Share Distribution Center (SDC). This paper shows that Bao, et al.’s scheme suffers from the proxy relationship inversion attack and forgery attack, and pro- poses an improvement of Bao, et al.’s scheme.
基金Supported by the National Natural Science Foundation of China (No.60503005)the Natural Science Foundation of Hunan Province (No.07JJ6110)
文摘Kang, et al. [Journal of Electronics(China), 23(2006)4] proposed a threshold multi-proxy multi-signature scheme, and claimed the scheme satisfies the security requirements of threshold multi-proxy multi-signature. However, in this paper, two forgery attacks are proposed to show that their schemes have serious security flaws. To overcome theses flaws, an improvement on Kang, et al.’s scheme is proposed.
基金supported by the National Natural Science Foundation of China (Grant No. 11204279)
文摘In the YW threshold proxy quantum signature scheme proposed by Yang and Wen,it is found that the basic signature key is the same as the basic verification key,which means that the bitwise exclusive OR(XOR) of the t proxy signature keys is exactly the XOR of the t proxy verification keys.Therefore,the proxy signers can deny their signature and the specific verifiers can forge a legal signature.Furthermore,an attacker can obtain a legal threshold proxy signature for an arbitrary new message.These findings show that there are hidden security loopholes that should be carefully constructed in designing more efficent YW-scheme.
基金the National Natural Science Foundation of China(Nos.60703031,60703004)the National High Technology Research and Development Program(863)of China(No.2006AA01Z4220the National Basic Research Program(973)of China(No.2007CB311201)
文摘The universal composability framework is a new approach for designing and analyzing the security of cryptographic protocols.In this framework,the security of protocols is maintained under a general protocol composition operation.In the paper,we propose the universal composability framework for the analysis of proxy threshold signature and present a universally composable secure proxy threshold signature scheme which is the first one in this area.The proposed scheme is suitable for the mobile agents,which should migrate across different environment through network.Furthermore,we give the concrete analysis of the reduction to prove the security of the proposed scheme.